text: The reciprocal to a simple hexagonal Bravais lattice with lattice constants  and  is another simple hexagonal lattice with lattice constants  and  rotated through 90° about the c axis with respect to the direct lattice. The simple hexagonal lattice is therefore said to be self-dual, having the same symmetry in reciprocal space as in real space. Primitive translation vectors for this simple hexagonal Bravais lattice vectors are